The Japanese swords are produced by a unique technology from tamahagane, a type of steel made in the Japanese tradition from iron sands.
The blade is forged through a lengthy process of hammering and folding, then the steel is hardened in two layers, by applying clay on the edge. Thus, the edge becomes harder, while the back of the blade remains softer, making it flexible. This process creates a beautiful and unique pattern where the harder and softer layers meet, pattern called hamon, which varies with each master swordsmith and school.
Photographed here is a sword with an spelendid hamon, seen at the Iwakuni castle, in Yamaguchi.
Yesterday’s Japan Photo: